Self-regulating gastric band with pressure data processing

Abstract

A self-regulating gastric band apparatus for adjusting stoma size is disclosed. The apparatus includes an adjustable gastric band that has an expandable portion containing a volume of fluid. A band adjustment assembly is provided for implanting with the gastric band that includes a sensor for sensing fluid pressure in the expandable portion. The band adjustment assembly further includes a pump assembly connected to the expandable portion and to a controller that can operate the pump assembly to adjust the volume of the fluid in the band based on the sensed fluid pressure. The band adjustment assembly includes memory storing an operating range relative to a target fluid pressure, and the pump assembly is operated to maintain the sensed band pressure within the operating range. The target pressure is set to maintain pressure variations below a predefined variation limit generally corresponding with satiated fill volumes for a particular patient and implanted band.

1. A gastric band adjustment assembly for placement in a patient with an implantable gastric band, the band adjustment assembly comprising:
 a sensor for taking pressure readings of fluid in a lumen of an expandable portion of the gastric band; 
 a pump assembly connected to the lumen; 
 a controller for operating the pump assembly to adjust a volume of fluid in the lumen based on the pressure readings and a target pressure for the gastric band; and 
 a pressure adjusting module for processing the pressure readings and setting the target pressure based on the processing of the pressure readings; 
 wherein the processing of the pressure readings comprises determining pressure variations each comprising a difference between a maximum and a minimum pressure at first and second values for the volume of fluid, and wherein the target pressure corresponds to one of the first and second values for which the pressure variations are determined to be lower or for which the pressure variations are within an acceptable range based on data analysis of the pressure readings by the pressure adjusting module over multiple sets of the pressure readings, and 
 wherein the setting of the target pressure comprises determining the pressure variations at the first value for the fluid volume are less than a maximum pressure variation value accessible to the pressure adjusting module, determining the pressure variations at the second value for the fluid volume are at least about the maximum pressure variation value, and setting the target pressure to correspond to the first value for the fluid volume. 
 
     
     
       2. The assembly of  claim 1 , wherein the pressure adjusting module processes the pressure readings to identify a fill volume of the fluid in the expandable portion at which pressure variations are less than a preset maximum pressure variation. 
     
     
       3. The assembly of  claim 2 , wherein the preset maximum pressure variation is less than about 0.3 pounds per square inch (PSI). 
     
     
       4. The assembly of  claim 2 , wherein the pressure adjusting module identifies the fill volume after the expandable portion has been filled to a nominal volume, the fill volume being greater than the nominal volume. 
     
     
       5. The assembly of  claim 1 , wherein the controller operates the pump assembly to increase the volume of the fluid in the lumen when a sensed fluid pressure determined from the pressure readings is below a lower pressure boundary value and to decrease the volume of the fluid in the lumen when the sensed fluid pressure is above an upper pressure boundary value and wherein the target pressure is between the lowers and upper pressure boundary values. 
     
     
       6. The assembly of  claim 5 , wherein the band adjustment assembly further comprises memory for storing the lower and upper pressure boundary values and the target pressure, wherein the pressure adjusting module operates to determine whether the sensed fluid pressure is between about the lower pressure boundary value and the upper pressure boundary, and wherein the pump assembly is operated by the controller until the pressure is determined to be at about the target pressure between the boundary values. 
     
     
       7. The assembly of  claim 5 , further comprising a communication module for receiving command signals from a monitoring device external to the patient, wherein the command signals comprise at least one of a new lower pressure boundary value, a new upper pressure boundary value, and a new target pressure, and wherein the new boundary values and the new target pressure are stored in the memory for use by the pressure adjusting module in processing subsequent pressure readings. 
     
     
       8. The assembly of  claim 1 , further comprising a fluid reservoir configured for storing a volume of the fluid for use in the adjusting of the volume of fluid in the lumen, the fluid reservoir being in fluid communication with the pump assembly. 
     
     
       9. The assembly of  claim 1 , further comprising a local controller communicating with the band adjustment assembly controller to provide command signals to operate the pump assembly and to retrieve information gathered by the band adjustment assembly controller and determined by the pressure adjusting module, wherein at least a portion of the pressure readings are provided in a graph on a display portion of the local controller. 
     
     
       10. The assembly of  claim 1 , further comprising a communication module linked to the controller and a manual port operatively coupled to the lumen for adjusting the volume of the fluid based on the pressure readings along with results of the processing by the pressure adjusting module both of which are at least partially transmitted to and displayed on an external monitoring device. 
     
     
       11. A gastric band adjustment assembly for placement in a patient with an implantable gastric band, the band adjustment assembly comprising:
 a sensor taking pressure readings for a volume of fluid in a lumen of an expandable portion of the gastric band; 
 means for adjusting a stoma created by the band in the patient proximate to the lumen; 
 a controller operating the adjusting means relative to the pressure readings and a target pressure for the gastric band; and 
 a pressure adjusting module processing the pressure readings and setting the target pressure based on the processing of the pressure readings; 
 wherein the processing of the pressure readings comprises determining pressure variations each comprising a difference between a maximum and a minimum pressure at first and second values for the volume of fluid, and wherein the target pressure corresponds to one of the first and second values for which the pressure variations are determined to be lower or for which the pressure variations are within an acceptable range based on data analysis of the pressure readings by the pressure adjusting module over multiple sets of the pressure readings, and 
 wherein the setting of the target pressure comprises determining the pressure variations at the first value for the fluid volume are less than a maximum pressure variation value accessible to the pressure adjusting module, determining the pressure variations at the second value for the fluid volume are at least about the maximum pressure variation value, and setting the target pressure to correspond to the first value for the fluid volume. 
 
     
     
       12. The assembly of  claim 11 , wherein the pressure adjusting module processes the pressure readings to identify an ideal stoma size at which pressure variations are less than a preset maximum pressure variation. 
     
     
       13. The assembly of  claim 12 , wherein the preset maximum pressure variation is less than about 0.3 pounds per square inch (PSI). 
     
     
       14. The assembly of  claim 11 , wherein the controller operates the adjusting means to create a smaller stoma when a sensed pressure determined from the pressure readings is at or below a lower pressure boundary value and to create a larger stoma when the sensed pressure is at or above an upper pressure boundary value and wherein the target pressure is between the lower and upper pressure boundary values. 
     
     
       15. The assembly of  claim 14 , wherein the band adjustment assembly further comprises memory for storing the lower and upper pressure boundary values and the target pressure. 
     
     
       16. The assembly of  claim 15 , further comprising a communication module for receiving command signals from a monitoring device external to the patient, wherein the command signals comprise at least one of a new lower pressure boundary value, a new upper pressure boundary value, and a new target pressure, and wherein the new boundary values and the new target pressure are stored in the memory for use by the pressure adjusting module in processing subsequent pressure readings.